Doing this imports the module GHC from the package ghc, which comes with GHC 6.5 and subsequent. The module GHC exports the "GHC API", which is still in a state of flux. Currently it's not even Haddock-documented. You can see the source code (which is somewhat documented) here
http://darcs.haskell.org/ghc/compiler/main/GHC.hs

Here's an example main program that does it Media:Main.hs. To compile Media:Main.hs, you have to turn on the flag "-package ghc", e.g.

ghc -package ghc Main.hs

1.2 Using the GHC library from inside GHCi

This works, to some extent. However, beware about loading object code, because there is only a single linker symbol table in the runtime, so GHCi will be sharing the symbol table with the new GHC session.